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Extract first set of records in JSON C#

I have a requirement to get the first set of records in c# JSON. Here is my JSON data for example
string sJSON = "{
{
"ID": "1",
"Name":"John",
"Area": "Java" ,
"ID": "2",
"Name": "Matt",
"Area": "Oracle" ,
"ID": "3","Name":
"Danny","Area": "Android"
}
}"
I need to extract only the 1st set of records (i.e. {{"ID": "1", "Name":"John", "Area": "Java"}}).
If there is only one record my code (see below) works fine but when there are multiple records it takes the last set of JSON data (i.e. {{"ID": "3","Name": "Danny","Area": "Android"}}).
JObject jsonObject = JObject.Parse(sJSON);
string sID = (string)jsonObject["ID"];
string sName = (string)jsonObject["Name"];
string sArea = (string)jsonObject["Area"];
Can anyone help me extract only the 1st set of JSON data?

You return the JSON data as JSON Array, now it is a simple JSON string.
If you're able to generate like below then you can easily get the single JSON element easily.
[{ "ID": "1", "Name":"John", "Area": "Java" },{ "ID": "2","Name": "Matt","Area": "Oracle" },{ "ID": "3","Name": "Danny","Area": "Android" } ]
Use the below link, to understand this JSON format.
http://json.parser.online.fr/

Parse the data as JToken.
Such that you have something like:
var jToken = JToken.Parse(sJSON);
var isEnumerable = jToken.IsEnumerable()
if(isEnumeable)
{
cast as JArray and get firstOrdefault
}
var isObject = jToken.IsObject();
if(isObject )
{
cast as JObject and perform straight casting
}

Json to C# object with google spreadsheet

EDITED:
If I load a google spreadsheet using JSON URL into a dynamic C# object, I can't access some entries because the JSON looks like this:
"author": [
{
"name": {
"$t": "XYZ"
},
"email": {
"$t": "XYZ#gmail.com"
}
}
]
Why does the google JSON have $ namespaces? Can we remove them? What can be done?
Here is the code:
var json = new WebClient().DownloadString(#"GoogleUrlWithJson");
dynamic jsonObj = JsonConvert.DeserializeObject(json);
string a = jsonObj.feed.entry[0].author.name.$t; ==> Can't compile error "unexpected $"

Try using square bracket syntax to access the JSON property names that have $ in them:
string a = jsonObj.feed.entry[0].author.name["$t"];

Convert specific attribute value in a JSON object to IEnumerable in C#

I have a JSON object that looks like this
{
"totalCount": 2,
"students": [{
"name": "abc",
"data": {
"Maths": 20,
"Science": 25
},
"score": 10.0
},
{
"name": "xyz",
"data": {
"Maths": 44,
"Science": 12
},
"score": 11.0
}]
}
I want to deserialize this JSON object to an IEnumerable<String> that contains all the names.
I want -
private IEnumerable<String> GetAllNames(string json) to return ["abc","xyz"]
This is just sample data (and not homework!!). Any advice on how to achieve this would be appreciated. I'm using Newtonsoft library but haven't been able to do this effectively yet. I do not want to iterate through the objects and construct the list myself, any direct way of doing this?
EDIT -
This is what I'm doing currently
var studentList = new List<string>();
var json = JsonConvert.DeserializeObject<dynamic>(jsonString);
foreach (var data in json.students)
{
catalogsList.Add(data.name.toString());
}
return catalogsList;

Try this:
private IEnumerable<string> GetAllNames(string json)
{
JObject jo = JObject.Parse(json);
return jo["students"].Select(s => s["name"].ToString());
}

Can I LINQ a JSON?

This is the JSON I get from a request on .NET:
{
"id": "110355660738",
"picture": {
"data": {
"url": "https://fbcdn-profile-a.akamaihd.net/hprofile-ak-prn2/1027085_12033235063_5234302342947_n.jpg",
"is_silhouette": false
}
}
}
and I'd like to catch the field "url", using (maybe?) LINQ. I do many request as this, that differents a bit. So I won't to create a C# Class and deserialize it every time.
Is it a way to extract a single field? Thank you!

No need for Linq, just use dynamic (using Json.Net)
dynamic obj = JObject.Parse(json);
Console.WriteLine((string)obj.picture.data.url);
Linq version would not be much readable
JObject jObj = JObject.Parse(json);
var url = (string)jObj.Descendants()
.OfType<JProperty>()
.Where(p => p.Name == "url")
.First()
.Value;
Documentation: LINQ to JSON

I would not recommend LINQ. I would recommend a JSON library such as newtonsoft.json.
So you can do this:
string json = #"{
""Name"": ""Apple"",
""Expiry"": "2008-12-28T00:00:00",
""Price"": 3.99,
""Sizes"": [
""Small"",
""Medium"",
""Large""
]
}";
JObject o = JObject.Parse(json);
string name = (string)o["Name"];
// Apple
JArray sizes = (JArray)o["Sizes"];
string smallest = (string)sizes[0];
// Small
Note:- this code has been copied from the samples present on the project site
http://james.newtonking.com/pages/json-net.aspx

In a bind you could always deserialize the JSON and serialize it to XML, and load the XML in a XDocument. Then you can use the classic Linq to XML. When you are done take the XML, deserialize it, and serialize it back to JSON to JSON. We used this technique to add JSON support to an application that was originally built for XML, it allowed near-zero modifications to get up and running.

You can easily query with LINQ like this
considering this JSON
{
"items": [
{
"id": "10",
"name": "one"
},
{
"id": "12",
"name": "two"
}
]
}
let's put it in a variable called json like this,
JObject json = JObject.Parse("{'items':[{'id':'10','name':'one'},{'id':'12','name':'two'}]}");
you can select all ids from the items where name is "one" using the following LINQ query
var Ids =
from item in json["items"]
where (string)item["name"] == "one"
select item["id"];
Then, you will have the result in an IEnumerable list

Generate lightweight JSON using DataContractJsonSerializer

I'm trying to generate JSON using C# and DataContractJsonSerializer in .Net 3.5. The problem is that I can't figure out how to build the structure correct for the result I need.
I've tried to reproduce PHP's associative arrays using both hashtables, list objects and arraylists but can't figure out how to generate my result in the best way using DataContractJsonSerializer without having to create my own recursive loop for building JSON.
The closest approach is using the a Dictionary < string, Dictionary < string, string>> aproach but the result is too big as I can't "name" the keys.
This is what I get:
[
{
"Key":"status",
"Value":[
{
"Key":"value",
"Value":"ok"
}
]
},
{
"Key":"1",
"Value":[
{
"Key":"name",
"Value":"Result1"
},
{
"Key":"details",
"Value":"Result 1 details"
}
]
},
{
"Key":"2",
"Value":[
{
"Key":"name",
"Value":"Result2"
},
{
"Key":"details",
"Value":"Result 2 details"
}
]
},
{
"Key":"caller",
"Value":[
{
"Key":"value",
"Value":"1135345"
}
]
}
]
This is what I want:
{
"status":"ok",
"response":[
{
"id":1,
"name":"Result1"
"details":"Result 1 details"
},
{
"id":2,
"name":"Result2"
"details":"Result 2 details"
},
{
"id":3,
"name":"Result3"
"details":"Result 3 details"
],
"caller":"1135345"
}
Does anybody have a clue how I can generate this piece of JSON using C# without having to load the entire Json.NET framework? I need this to be generated as fast as possible as this project aims to become an site search engine.

You should look at using the JavaScriptSerializer. It's part of the .NET framework (distributed in System.Web.Extensions). To get the result you want you can do this:
var results = new[]
{
new{id=1,name="Result 1"},
new{id=2,name="Result 2"},
new{id=3,name="Result 3"}
};
var js = new JavaScriptSerializer();
var result = js.Serialize(new
{
status = "ok",
response = results,
caller = 1135345
});
You can either use anonymous classes, or any existing ones. Works perfectly fine :)
The return value of this call would be:
{"status":"ok","response":[{"id":1,"name":"Result 1"},{"id":2,"name":"Result 2"},{"id":3,"name":"Result 3"}],"caller":1135345}

Using the JavaScriptSerializer rather than DataContractJsonSerializer on a Dictionary will remove the Key/Value json attributes and make them into a "keyed" array.
http://msdn.microsoft.com/en-us/library/bb412168.aspx
Have you attributed your classes with the [DataContract] and [DataMember] decorators?
http://msdn.microsoft.com/en-us/library/bb412179.aspx